The One Direction heartthrob is said to have broken up with his childhood sweetheart because he was worried they couldn't cope with him being away on a 69-date world tour with his band.

A source told The Sun newspaper: ''Liam and Sophia were inseparable and he couldn't believe his look when he finally landed the girl he'd spent his schooldays dreaming would one day go out with him.

''But they just didn't know how they would be able to make a long-distance romance work. So Liam made the painful decision to end it.

''It has been really hard for him, all alone on the other side of the world so soon after going through a break-up. But the huge crowds of fans flocking to their gigs every night have given him everything he needs to keep going.''

Although Liam is upset about the split - bringing an end to their nine-month romance - he realised it was fairer for both of them.

The insider added: ''Liam said she is the sweetest girl he's ever met and he's really sad about the split. But he knows it was the right thing to do.

''He wants her to enjoy university and not be sad waiting for him to come back from tour for the odd day here and there.''